Eye for an Eye
by YankeeFan87
Summary: During one of the boys' prank wars, Sam puts eye drops in Dean's beer and Dean becomes violently ill. Just some good old fashioned whumping here...tons of Sick!Dean.


**A/N: **Wrote this for a comment-fic meme and kinda got carried away. Not much plot to this story, simply what I stated in the summary. Anyways, I hope you guys enjoy it! Let me know what you think!

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><p>Dean looked over at Sam as he stirred slightly in the passenger seat of the Impala, smiling as he saw the tufts of uneven hair where the Nair had caused some of it to fall out. Yes, Ladies and Gentlemen, Dean Winchester had pulled the Nair-in-the-shampoo bottle prank again, and it had worked damn well. Sam had been <em>pissed<em> when he'd realized what Dean had done, not even slightly amused by Dean's explanation that he was doing Sam a favor, helping to trim that huge mop of hair he had on his head.

The latest prank war had started out innocently enough, but three days of researching and scoping out a hunt which turned out to be a hoax in the end had caused both of them to become cranky and bored. The pranks had escalated as each brother continually tried to one-up the other. And the Nair prank had been the best so far, if Dean could say so himself.

"Sam," Dean said quietly when Sam stirred again, shaking his brother's shoulder lightly. It was nearly 3 PM and Dean had been driving since 8 that morning, intent on reaching their next destination – a haunting in Bloomington, Indiana – by that evening. Sam had been asleep almost the entire time and Dean was bored, hungry, and tired. He saw a sign for a diner at the next turn-off and gratefully took the exit, pulling into the moderately-crowded parking lot. Sam woke when Dean turned the engine off, looking over at his brother as he stretched.

"Where are we?" he asked drowsily.

"Lexington, Kentucky. Just a few hours out from Indiana. You hungry?"

Sam's stomach growled loudly and he looked at Dean, embarrassed. "Yeah I could eat."

Dean laughed, getting out of the car and stretching his arms out. Sam followed, doing the same as his brother. "Let's eat, then. I'm starving." Dean started heading towards the diner, turning around when he realized Sam wasn't following. "You coming?"

Sam nodded, running his hands through his hair. "Yeah I'll be there in a minute. Why don't you go get us a table?"

Dean shrugged. "Gonna try and fix your hair, Sammy?" he mocked.

Sam shot him an icy glare. "This isn't over, you know."

Dean barked out a laugh, walking towards the diner. "Bring it, bro," he shouted over his shoulder.

Sam reached back into the car, grabbing the tiny bottle of eye drops he'd gotten on their last supply run a few days ago. At the time, Sam hadn't even been considering using it against Dean, but his big brother was totally asking for it. Sam smiled a little, remembering the first time he'd been introduced to this particular method of revenge. His freshmen year at Stanford, Sam, his roommate Aaron, and a few of the other guys on his floor had gotten into a full-out prank war. They'd done stuff to each other that would put Dean and Sam's pranks to shame. At the height of the prank war, Aaron had slipped a few drops of eye drops into Sam's beer one night, leaving Sam with the worst case of the runs he could ever remember. He'd spent the entire night holed up in the bathroom, unable to stray far from the toilet.

After a night of hell, though, he'd felt a thousand times better in the morning. Sure, he was a little shaky and a little embarrassed, but he had to hand it to Aaron – that had been one hell of a prank. And now it was Dean's turn to see that he wasn't the best prankster in the family. He slipped the tiny bottle into his jacket, hurrying into the diner.

Dean was seated at a booth near the door and Sam slid in across from him. "I ordered us some beers," Dean told him, moving to stand up. "I'm gonna hit the head, be back in a few."

Sam nodded, picking up the menu to look. The waitress placed the beers on the table before Dean was back and Sam grinned – this was going to be too easy. He looked towards the bathroom, making sure Dean wouldn't see what he was doing, and carefully squeezed three drops into Dean's drink. He had just placed the bottle back in his pocket when Dean returned. "Anything good?" he asked.

"Uhh," Sam stuttered, "didn't really get a chance to look."

Dean eyed the open menu pointedly. "Then what've you been doing?"

Sam waited a second, silently freaking out in his head. _Why was he so bad at lying?_ "Checking out the waitresses," he said, surprisingly smoothly. It was only after he said it that he realized Dean would never buy that.

"Checking...what the? _You_?" Sam nodded tightly, eyes returning to the menu. Dean was about to question him again when the waitress approached and he decided to turn his attention to her.

"Hey guys!" she said warmly, and Dean returned her greeting with a brilliant smile. "Are you ready to order?"

"Do you have any suggestions...Kelly?" Dean asked charmingly, looking at the name tag on her uniform.

She smiled back, blushing a little. "Burgers are our most popular sellers here," she told him, pointing to the menu where it listed the different kinds. "I would suggest the Triple Crown platter," she continued, "bacon cheddar cheeseburger with the works, a side of cheese fries, and a side of deep-fried onion rings."

"That sounds fantastic," Dean told her. "I'll have one of those." He closed his menu and took a swig of his beer.

Sam grimaced, knowing all that food and the eye drops would make for a very unpleasant evening. "What about you, hon?" Kelly asked Sam who was lost in thought.

"What do you suggest for someone who doesn't like to eat like a pig?" Sam asked, chuckling at the look Dean shot him.

Kelly frowned for a second, thinking, "We have a grilled chicken platter. Side of vegetables and mashed potatoes."

Sam folded his menu. "I'll take that. Thank you,"

Kelly smiled, taking the menus from the boys. "Great! Let me know if you need anything else."

Dean watched as she hurried off to the kitchen and Sam kicked his shin under the table. "What was that for?" Dean whined.

"Behave yourself."

Dean laughed, taking another pull from his beer. "So I figure we get to Bloomington tonight, crash for a few hours, and check out the school where the hauntings have been?"

_Shit_, Sam thought. _The hunt_. "Yeah, sounds good," he agreed, knowing that Dean probably wouldn't be up for much of anything tonight. He was starting to feel guilty about the prank but knew there was no going back now. Hopefully Dean wouldn't have it as bad as Sam had.

The food arrived quickly, and Sam had to admit it smelled fantastic. Even Dean's cheesy, fried food looked good to Sam.

"Thank you, sweetheart," Dean said when Kelly had finished setting down the food.

"No problem," she returned, winking at him before turning and heading to another table.

"You see that, Sam?" Dean asked excitedly. "She likes me."

"You're such a child," Sam scolded mildly, picking up his utensils and digging in.

Both boys scarfed down their dinners and their plates were nearly spotless when they finished. Kelly seemed especially pleased that they had liked their meals so much and she smiled broadly when they thanked her and headed out, leaving a nice tip.

"Want me to drive?" Sam asked, already headed towards the driver's seat. "You've already driven nearly 8 hours today, Dean. I know you're tired," he argued when Dean seemed to hesitate.

"Yeah okay," Dean agreed. "I could sleep." He tossed the keys to Sam, climbing into the passenger seat. "You know where we're headed?"

Sam held up the map. "Bloomington, right?" Dean nodded. "Yeah I think I can figure it out." Sam put the key into the ignition, pulling out of the diner parking lot and turning the dial on the radio until he found a nice mellow station.

"Seriously?" Dean asked, raising an eyebrow.

"I drive, I choose the music. Deal with it."

Dean mumbled something under his breath but let it go. "This music is gonna put me to sleep."

"Good," Sam agreed. "You look like you need it."

Dean hadn't intended to fall asleep but the combination of Sam's emo music and the comforting hum of the Impala's engine made it nearly impossible for him to stay awake. He was soon snoring softly, head pressed up against the window.

Sam smiled when he looked over, hoping the fact that Dean seemed okay now meant he wouldn't suffer too badly from Sam's prank. He was really starting to feel bad about it, even though Dean could be an ass at times.

It was another two hours before Dean started shifting in his seat, groaning slightly. Sam looked over, seeing Dean's pale face, sweat beading on his forehead. "Dean," Sam whispered, glancing between the road and his brother. Dean groaned again, wrapping his arm tightly around his stomach and opening his eyes to look over at Sam. "You okay, man?" Sam asked, already knowing the answer.

Dean tried to push himself higher in the seat. "Ugh, I feel awful," he told Sam once he'd gotten into a relatively comfortable position. "Do _you_ feel okay?"

Sam nodded. "Yeah Dean, I feel fine. Maybe it was the burger?" he asked, feeling like a complete ass.

Dean groaned again. "_Please_ don't mention food, Sam."

"Oh yeah. Sorry, man. Do you need me to pull over?"

Dean gulped hard. "Maybe in a little. Where are we?"

"Somewhere in Indiana. Should be in Bloomington in an hour and a half. Can you last that long? We could stop before that."

Dean shook his head tightly. "Nah, let's get there tonight. I'll be okay."

Dean closed his eyes again, trying his best to ignore the churning in his gut and the shaky feeling that had come over him. He knew he wouldn't be able to keep this up for long, but he really did not want to be spewing his guts all over the side of the road. He silently prayed he would be able to make it to Bloomington, knowing in his heart that there was very little chance of that.

Dean lasted another thirty minutes before the nausea became too overwhelming. He brought a shaky hand to his mouth. "Sam," he gulped out, hoping his brother would get the message. Sam had been watching Dean closely, knowing his brother was feeling worse and worse as the drive went on. So he had known exactly what to do when Dean had called out to him.

There was no one else on the road and Sam quickly pulled over onto a grassy patch just off to the side. He hurried over to Dean, who had already pushed open his door and stumbled to the back of the Impala. Dean was bent low, gripping the back fender, but he hadn't thrown up yet. "Dean?" Sam asked tentatively.

"Gonna be sick, Sam," Dean told him, as if that wasn't obvious already. The last word ended in a harsh gag. He gagged once more before bending over further and vomiting the contents of his stomach onto the yellowing grass. He continued to heave, pulling in shaky breaths between bouts, trying his best to hold on to the fender as his body shuddered from the effort of being sick. Sam got behind him, offering whatever assistance he could.

"You're okay," he soothed, knowing the words of comfort sounded hollow. "Just let it all out. You'll feel better soon."

Dean coughed and sputtered, spitting out strings of bile. "Th...think I'm done," he told Sam when it felt like he couldn't puke any more if his life depended on it. He fell backwards against his brother, energy almost completely spent. Sam led him over to the Impala, sitting him in the seat with his feet on the ground outside. He rummaged through the backseat, coming out with a water bottle. He cracked it open, holding it out for his brother. "Here, rinse and spit," he instructed. Dean took the water, his arm still shaking as he raised it to his mouth. He did as Sam had told him, handing back the bottle when he was done. Dean bent forward, his head almost touching his knees, moaning quietly.

"You gonna be sick again?" Sam asked, crouching down to look his brother in the eyes.

Dean nodded. "Probably. I'm okay now though, my stomach is just killing me."

Sam was starting to get concerned. He didn't remember feeling _this_ awful when he'd been a freshman. He helped Dean pull his feet back into the car, closing the door and returning to the driver's seat. Sam looked at Dean critically, taking in his gray pallor and the constant tremors running through his body. "We'll stop at the next motel I see," Sam told him decisively. He didn't want Dean to have to suffer the whole car ride to Bloomington.

"N...no," Dean said through his chattering teeth. "No Sam I'll be fine. Let's just...keep going. Please?" he wheedled, knowing Sam would have a hard time denying that.

Sam huffed out an exasperated breath. "You're sick, Dean. You really want to spend the next hour in a car?" Dean nodded jerkily. "Okay," Sam relented. "But if you need to stop, just tell me." Dean agreed, curling up again and humming quietly to himself. Sam reached over to the radio, putting on some classic rock instead of the slow music he'd been listening to earlier.

"Thanks Sammy," Dean mumbled drowsily, and Sam's guilt ratcheted up another notch.

The drive to Bloomington took far longer than it should have, with Sam having to pull over every ten miles or so for Dean to be sick. On more than one occasion he had been tempted to drive Dean straight to the hospital, but his brother's weak protests won him over. Besides, what would he tell the doctors? That his brother was sick because he'd poisoned him with eye drops? Still, Sam swore that if the situation got much worse, he'd bring Dean to the hospital, regardless of the consequences.

They reached the city limits shorty after 9 PM and Sam couldn't have been more relieved. He looked over at his brother, concerned that he wasn't even complaining anymore. Dean was listing now, having trouble staying conscious. Sam reached out and put his hand on Dean's shoulder, shaking it slightly. "Dean," he whispered. Dean stirred but didn't wake. "Dean," he said again, more loudly this time. Dean opened his eyes, hiccoughing slightly.

"Sam?" he asked, looking around and realizing the car had stopped. "We here?"

"Yeah we're here. Finally. I'm gonna go get us a room – can you try and drink a little water for me?" Dean accepted the water bottle from Sam, raising it to his mouth and taking a tiny sip. He tried to hand it back to Sam, but Sam put up a hand in protest. "A little more, Dean. You're gonna get dehydrated." He took the bottle back when Dean had drunk a sufficient amount. "Okay, man. I'll be right back."

Sam hurried into the motel office, handing a fake card to the matronly motel owner and successfully obtaining a room for three nights. Sam had no idea how long Dean would be sick, but he decided to err on the side of caution. Sam walked quickly back to the Impala, seeing Dean once again curled up on his side. He opened the passenger door slowly, reaching in and shaking Dean's knee. "C'mon, Dean. Let's get you inside." Dean got up slowly, using Sam's hand for support.

He swayed a little once he was vertical and Sam was certain he would have collapsed if he hadn't been holding him up. Sam kept a steadying arm around Dean as they walked to the door of their room. The motel was far nicer than the dumps they usually stayed in and for that Sam was grateful. He led Dean to the bed closest to the bathroom, knowing he would probably be needing it soon anyway.

Once Dean was settled, Sam hurried out to the car, grabbing their bags and a few water bottles and returning to the room. Dean was sitting up in bed, swallowing thickly. Sam dropped his bags on the floor, grabbing the trash can and quickly returning to his brother. He placed the can in front of Dean just as he started to heave, throwing up the water and whatever remained in his stomach. When he finished, he was panting heavily and groaning. "Dean?" Sam asked, concerned.

"Hurts," he moaned, listing to the side.

"Your stomach?" Sam asked, helping him lie down.

"Mmm...yeah," Dean murmured, rolling onto his side and pulling his knees up to his stomach.

Sam pulled the blankets up around him, turning off the lights and sinking down onto his own bed, exhausted and worried. After a little while, he pulled out his laptop, booting it up and connecting to the internet, typing "eye drop poisoning" into the search engine. "Shit," he murmured when he saw the results. Eye drop poisoning, it said, could not only cause diarrhea, it could also result in breathing difficulty, blood pressure fluctuations, seizures, and even coma. "Fuck!" Sam shouted a little too loudly, causing Dean to stir in the other bed.

"What's wrong?" Dean asked drowsily, raising his head slightly to look at his brother.

Sam shut the laptop quickly, feeling guilty. "Nothing man, just worried about you. How you feeling?"

"Shitty," Dean huffed out. "Actually speaking of that..." he tried to push himself up in the bed and Sam jumped up to help him.

"What're you doing?"

"Need...bathroom," Dean panted out, hunching over further.

"You gonna be sick again?" Sam asked, hand hovering near the trashcan in case Dean needed it. Dean shook his head, embarrassed, and Sam understood. "Okay just lean on me, man." They shuffled to the bathroom, Dean grabbing onto the door once they'd reached it.

"End of the line, Sam," Dean told him, weakly shoving his brother out of the tiny room.

"Dean, you can barely stand. Just let me help you."

Dean shook his head, resolute. "Don't need to stand. I'll yell if I fall...or somethin." Sam didn't budge and Dean bent low when his stomach gave an uncomfortable gurgle. "Saaaam," Dean whined. "Leave."

Sam gave Dean one last glace before turning and leaving the bathroom, closing the door softly behind him. He heard Dean's soft moan and he was about to knock on the door again but thought better of it. He returned to his bed, trying to block out the sounds of Dean's distress. Sam waited a few minutes before going back to the bathroom. "Dean," he said, knocking softly on the door. Dean returned his knock with a low moan.

"Go 'way Sam."

"Are you alright?"

"Peachy," he spat out. "Be a few more minutes."

Sam hesitated again. "Yeah okay," he agreed, deciding to give Dean his privacy. Five minutes later, Sam heard the toilet flush and the door open. He looked up to see Dean standing in the doorway, slightly hunched over and looking paler than Sam could ever remember seeing him. He quickly got off the bed and hurried to Dean's side, supporting him and lowering him down on the bed.

"Think I dropped 10 pounds in there, Sammy," Dean whispered breathily. Sam brought a hand up to Dean's forehead, frowning at how cold and clammy his brother was. Dean knocked his hand off weakly.

"Not sick," Dean argued.

"I can see that," Sam snorted. "So puking your guts out is a common occurrence?"

Dean rolled his eyes. "Not _sick_ sick. Just food poisoning...or something."

"Yeah or something," Sam murmured under his breath. He reached over and snagged the bottle of Pepto he'd retrieved from the first aid kit. "Wanna try this?" he asked, holding up the bottle for Dean to see. Dean grimaced, gulping. "It may help with the diarrhea," Sam continued.

Dean seemed to consider that, finally nodding slightly. Sam opened the bottle and measured some out. "Bottom's up," Dean said, chugging back the pink liquid. He swallowed thickly, trying to decide if it was going to stay down. When three minutes had passed without him spewing out the pink liquid, he thought it safe to lie down.

"Dean," Sam said quietly. "I'm gonna put the trash can by your bed, okay?" Dean grunted his understanding. "Let me know if you need anything else."

"Thanks," Dean whispered, curling up and closing his eyes.

Dean awoke a few hours later, gagging. He brought his hand to his mouth, desperately trying to find the garbage can before throwing up all over the floor, but it was no use. He heaved helplessly, vomiting Pepto Bismol and bile all over the sheets, gagging until he was gasping for breath.

Sam had been dozing in the other bed but woke up the second he heard his brother's struggles. "Dean!" he shouted, jumping up and hurrying to his side. He hovered by Dean's bed, waiting until he'd calmed some.

"Sorry," Dean said, looking up at Sam and then down at the mess.

"Don't worry about it, Dean. C'mon, let's get you cleaned up." Sam helped Dean stand and the two walked into the bathroom. Sam left Dean sitting on the toilet seat and he wet a wash cloth. "Let's get that shirt off of you," he suggested, gesturing to the now-soiled tee Dean was wearing. He helped Dean struggle out of the t-shirt, then handed him the wash cloth to clean up a little. When Dean was done and changed into a clean shirt, Sam helped him lie down on his own bed. "You okay here? I'm just gonna clean up the other bed."

"Yeah m'okay," Dean mumbled, already drifting back to sleep.

Sam removed the sheets, scrubbing the floor where Dean had thrown up. He threw everything into the bathtub along with Dean's shirt, planning on doing laundry the next day. Sam returned to the bedroom, expecting to see Dean sleeping, but instead he realized Dean was awake, violent shivers coursing through his body.

"Hey, hey," he said, crouching down by Dean's bed. "What's the matter?"

"C...o...ld. And dizzy."

"Shit," Sam murmured. "I'll get some more blankets. Do you think you can drink a little water?"

Dean shook his head jerkily. "Be...sick again."

Sam nodded, knowing he was probably right. "We'll try again in a little, then," he compromised. He went to the closet, grabbing all the extra blankets and piling them on top of his brother. Dean snuggled deeper under them until all Sam could see were the tufts of his hair.

"Night, Dean," he said quietly, praying Dean would be able to sleep soundly the rest of the night.

But Dean didn't sleep soundly, and in just a little over an hour he was stirring, looking miserable. Sam got up from the chair he'd been sitting in, intending to see what Dean needed, when Dean jumped up and raced to the bathroom. Sam followed after slowly, finding Dean in a desperate crouch in front of the toilet, heaving violently. Sam couldn't believe he had anything left _to_ throw up, but Dean proved him wrong, vomiting again and again into the water. He collapsed against the bathtub when he was finished, his shirt now soaked through with sweat.

Sam flushed the toilet, filling a glass with water and returning to Dean. Dean opened one eye, glaring at the proffered glass and pushed it away. "Can't," he said simply.

"I know you don't wanna puke anymore Dean, but you need this. You're dehydrated." Dean set his mouth stubbornly, refusing to open it. "Okay hospital it is then," Sam told him, pulling out his cell phone.

"No!" Dean shouted with more energy than Sam thought he had. "No hospital, Sammy. Please?"

"Then you have to drink this. Just a little." Dean gave in, taking the glass from Sam and sipping from it. He looked up at Sam, waiting for his approval. "A little more, Dean." Dean took a few more sips before his stomach started protesting and he knew he'd be seeing the water again soon if he didn't stop. "Fine," Sam said, taking the glass from him. "You ready to go back to bed?"

Dean shook his head. The nausea was already returning and the roiling in his gut told him he'd be needing the bathroom very shortly. "Think I'll stay here," he mumbled, teeth chattering.

Sam was going to protest but instead decided Dean probably knew best what he needed right now. He went to the bedroom, grabbing the blankets and some pillows and tried his best to make Dean comfortable. He sat on the bathtub, watching as his brother curled up again, quivering under the blankets.

As it turned out, it was a very good idea they'd stayed in the bathroom. Dean was up and puking again after less than thirty minutes and Sam was really starting to get worried. He'd never seen Dean this sick before, especially not from something that he had caused. "Kill me now," Dean groaned, spitting once more into the toilet.

"Sorry man, no can do." Sam thought back to the symptoms he'd seen on the internet. "How's your breathing, Dean?"

Dean looked at him questioningly. "It's okay. My stomach's what hurts," he pointed out, as if that wasn't obvious already.

"Nothing else? You said you were dizzy before. Do you still feel light headed?"

"What's with the...twenty questions, Sammy?"

"Just want to make sure you don't need a doctor."

Dean shook his head petulantly again. "No doctor."

"Dean," Sam sighed, ready to tell him about the eye drops. "It could be serious."

"Just feels like food poisoning," Dean argued, clearly done with the conversation.

"Dean..."

"Sam," he broke in. "Just lemme sleep. Be fine in the morning." Sam studied him, not saying anything. "Go to bed, Sammy," Dean mumbled.

Sam got up, moving into the bedroom. He didn't want to leave his brother, but he figured Dean wanted some privacy. He climbed into the bed, sitting against the wall and tipping his head back. He looked over at the bathroom where light was spilling out from the slightly-opened door, couldn't believe that his brother was in there, sick as a dog because of him.

Sam found himself drifting off to sleep again, jerking awake minutes or hours later. He listened for any sounds, from the bathroom, getting up and approaching the door when he didn't hear anything. Sam pushed it open to find Dean still curled up, chest rising and falling steadily in sleep. Sam took his a seat on the bathtub, watching his brother closely. He was still sitting there when the sun came out, light streaming through the blinds in the bathroom window.

Dean hadn't so much as stirred and for that Sam was immensely grateful, hoping that meant that the illness had passed. When the birds started singing outside, Dean finally awoke, looking up at Sam and taking a few seconds to remember everything that had happened.

"Guess I'm not dead?" he asked, his voice gravelly and dry.

Sam got up and retrieved a glass of water for him which Dean took and drank greedily. "Nope, not dead. You look better."

Dean nodded, handing the glass back to Sam and struggling to stand. "Feel a lot better. God that sucked."

"Yeah," Sam agreed, following Dean into the bedroom.

"What's wrong, Sammy? You look like somebody kicked your dog."

Sam sat on the edge of his bed, looking across at Dean. "Dean," he started slowly, not knowing how his brother would react. "Last night – that wasn't food poisoning."

"Huh?" Dean asked, clearly oblivious to what Sam was trying to tell him.

"It was me, my fault. I wanted to get back at you for the Nair...so I put eye drops in your beer. I didn't think you would get so sick. Believe me, if I had any idea..." Dean just stared at Sam, wearing an expression of surprise and disbelief. And then he started laughing. He laughed so hard he couldn't catch his breath, holding his stomach as he shook with laughter.

"Dammit man, that hurts," he said accusingly.

"You're not mad?" Sam asked, completely taken aback.

"Mad? Nah, how could I be mad? I'm impressed."

"Impressed? Dean, you were seriously ill."

Dean seemed to consider that for a minute, then shrugged and threw a pillow at his brother instead. "S'ok Sammy. Anything goes in our prank wars. But you better watch your back. I owe you big time."

Sam watched as his brother stretched out in his bed, still chuckling lightly to himself. He lay back too, knowing he'd need the rest. It was going to be a long few days and Sam knew he'd have to be extra alert for any of Dean's pranks. After all, payback was a bitch.

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><p><em>Reviews? Muah!<em>


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